Prostaglandins E, E plus A plus B, F alpha, 15-keto-PGE, 15-keto-PGF alpha, 13, 14-dihydro-15-keto-E, 13, 14-dihydro-15-keto-PGF alpha, and 13, 14-dihydro-PGF alpha will be measured in normal and malignant tissues and in culture fluids after maintenance of these tissues in organ culture. The following enzymes involved in the biosynthesis and metabolism of the prostaglandins will also be measured in these tissues before and during maintenance in tissue culture; 1) 15-hydroxy-prostaglandin dehydrogenase (Types I and II), 2) delta 13, 14 reductase, 3) prostaglandin interconvertase (PGE yields (reversibly) PGF), and 4) prostaglandin synthetase. All of these prostaglandins and their metabolites as well as the enzymes will be measured with the use of specific antibodies directedtoward the product, the substrate or both.